Screening plant system

Abstract

A system and method for carrying out a combined crushing and screening operation on a supply of bulk raw material, and utilizing a crusher and a self-propelled screening plant to receive a supply of crushed material from the crusher via an input end of the plant, in which the input end of the screening plant includes a preliminary screening unit which separates over-sized crushed material and directs the remainder of the material to a screen box of the plant, and a conveyor unit cooperates with the screening plant to receive over-sized material from the preliminary screening unit and discharges the over-sized material to a stockpile and/or recycles the material to the crusher for further crushing. The conveyor unit may be coupled with the screening plant via lockable lift arms and cooperating housing when they work together to form a composite assembly which can be maneuvered on site when required.

1 . A system for carrying out a combined crushing and screening operation on a supply of bulk raw material, and utilizing a crusher to crush a supply of bulk raw material fed thereto, and a self-propelled screening plant to receive a supply of crushed material from the crusher via an input end of the plant, said plant being operative to screen the crushed material into at least one size range of crushed material; 
 in which;    the input end of the screening plant includes a preliminary screening unit which is operative to separate out over-sized crushed material from the supply of crushed material and to direct the remainder of the material to at least one screen box of the plant; and    a conveyor unit is co-operative with the screening plant to receive over-sized material from the preliminary screening unit, and operative (a) to discharge the over-sized material to a stockpile and/or (b) to re-cycle the material to the crusher for a further crusher treatment, said conveyor unit being capable of being coupled with the screening plant when they work together, and of being an independent free standing unit when uncoupled from the screening plant.    
     
     
         2 . A system according to  claim 1 , in which the conveyor unit is capable of being coupled with the screening plant to form a composite assembly which is maneuverable on site with the conveyor unit being supported by the screening plant.  
     
     
         3 . A system according to  claim 2 , in which the coupling together of the conveyor unit and the screening plant is provided by inter-engaging lift arms and housings.  
     
     
         4 . A self-propelled screening plant which comprises: 
 an input end for receiving a supply of crushed material;    a screen box;    a preliminary screening unit provided at the input end and operative to separate out over-sized crushed material from the supply of crushed material and to direct the remainder of the material to the screen box; and    a conveyor unit co-operative with the screening plant to receive over-sized material from the preliminary screening unit, and operative (a) to discharge the oversized material to a stockpile and/or (b) to re-cycle the material to the crusher for a further crusher treatment, said conveyor unit being capable of being coupled with the screening plant when they work together and of being an independent freestanding unit when uncoupled from the screening plant.    
     
     
         5 . A self-propelled screening plant according to  claim 4 , in which the conveyor unit and the screening plant are capable of being coupled together by inter-engaging lift arms and housings.  
     
     
         6 . A self-propelled screening plant according to  claim 4 , in which the conveyor unit has a tandem arrangement of parallel conveyors, extending generally perpendicular to the longitudinal axis of the plant, and the input end of the plant has a discharge chute or the like which discharges over-sized material to one or the other of the conveyors of the conveyor unit.  
     
     
         7 . A self-propelled screening plant according to  claim 6 , in which one conveyor of the conveyor unit is operable to form a stockpile of over-sized material.  
     
     
         8 . A self-propelled screening plant according to  claim 6 , in which one of the conveyors of the conveyor unit is operative to deliver over-sized material for recycling to a crusher, when the latter is located adjacent to the conveyor unit.  
     
     
         9 . A self-propelled screening plant according to  claim 4 , in which power to operate the conveyor unit is transmitted via an umbilical connection to the screening plant.  
     
     
         10 . A self-propelled screening plant according to  claim 4 , in which the screening plant has a set of crawler or endless tracks to enable the plant, or the plant and the conveyor unit when coupled therewith, to be maneuvered on site, and in which the conveyor unit has adjustment means to facilitate height adjustment to cooperate with the input end of the plant.  
     
     
         11 . A method of carrying out a combined crushing and screening operation on a supply of bulk raw material, and utilizing a crusher to crush a supply of bulk raw material fed thereto, a self-propelled screening plant to receive a supply of crushed material from the crusher via an input end of the plant and which is operative to screen the crushed material into at least two size ranges of screened material; 
 in which the input end of the screening plant includes a preliminary screening unit operative to separate out over-sized crushed material from the supply of crushed material and to direct the remainder of the material to at least one screen box of the plant for screening the material into at least two screened size ranges of material to be delivered to discharge means which forms separate stockpiles of screened material; and,    a separate conveyor unit co-operative with the screening plant to receive the oversized material discharged which discharges the oversized material from the preliminary screening unit and to discharge to (a) a further stockpile and/or (b) to be recycled to the crusher for a further crushing treatment.    
     
     
         12 . A method according to  claim 11 , in which the screening plant is maneuvered away from the separate conveyor unit, and carries out screening operations at any other required location on site.  
     
     
         13 . A method according to  claim 11 , in which the screening plant and the separate convey screened material for unit are relatively adjustable to facilitate relative movement of the plant and the conveyor unit towards and away from co-operative interengagement.  
     
     
         14 . A method according to  claim 11 , in which the plant is able to maneuver itself via a set of crawler or endless tracks, and the conveyor unit has adjustment means to facilitate height adjustment to co-operate with the input end of the plant.  
     
     
         15 . A method according to  claim 11 , in which power to operate the separate conveyor unit is transmitted via an umbilical connection to the screening plant.  
     
     
         16 . A method according to  claim 11 , in which the conveyor unit has a tandem arrangement of parallel conveyors, extending generally perpendicular to the longitudinal axis of the plant, and the input end of the plant has a discharge chute or the like which discharges oversized material to one or the other of the conveyors of the conveyor unit.  
     
     
         17 . A method according to  claim 16 , in which one conveyor of the conveyor unit is operated to form a stockpile of oversized material.  
     
     
         18 . A method according to  claim 16 , in which one of the conveyors of the conveyor unit is operated to deliver oversized material which is recycled to the crusher.  
     
     
         19 . A freestanding conveyor unit for use in a method according to  claim 11.